Climbing the Distance Ladder to the Big Bang: How Astronomers Survey the Universe  –  Dragan Huterer
The furthest objects that astronomers can observe are so distant that their light set out when the Universe was only 800 million years old, and has been traveling to us for about 13 billion years-most of the age of the Universe. Even the Sun’s neighborhood – the local part of our Galaxy, where astronomers have successfully searched for planets around other stars – extends to hundreds of light years. How do we measure the distance to such remote objects? Certainly not in a single step! Astronomers construct the so-called “Distance Ladder,” finding the distance to nearby objects, thus enabling those bodies to be understood and used as probes of yet more distant regions. The first steps in the ladder uses radar ranging to get the distance to the nearby planets and the Sun; and ‘triangulation’ to get the distances to the nearest stars. Those in turn are used to obtain distances to other stars in our Milky Way Galaxy, stars in other galaxies, and out to the furthest reaches of what is observable. This class will explore the steps in this ladder, using lectures, discussions, field trips, demonstrations, and computer laboratory exercises. Students will learn basic computer programming for a project to model the effects of gravity, and they will get hands-on experience of using a small radio telescope to map the the rotation speed of the Milky Way and measure the influence of its dark matter. We will cover concepts involving space, time, and matter that go far beyond the distance ladder, and involve some of the most fascinating mysteries in cosmology and astrophysics: What is it like inside a black hole? What is the Dark Matter? What is the Dark Energy that makes the Universe expand faster and faster? Is there other life in the Universe?